Nanofibrillated cellulose ply bonding agent or adhesive and multi-ply absorbent sheet made therewith

Abstract

A ply-bonding agent or adhesive composition characterized by a viscosity and a surface tension for the manufacture of paper tissue and paper towel, includes: (a) water; (b) nanofibrillated cellulose; and (c) one or more modifiers effective to modify either or both of (i) the viscosity of the composition or (ii) the surface tension of the composition, wherein the one or more additional modifiers are selected from the group consisting of components (iii), (iv), (v), (vi), (vii) or (viii), wherein: (iii) is PVOH and a viscosity modifier; (iv) is a viscosity modifier; (v) is a viscosity modifier and a surface tension modifier other than PVOH; (vi) is a water-soluble cellulose derivative; (vii) is a water soluble polyol; and (viii) is a surface tension modifier other than PVOH. The compositions are particularly useful for ply-bonding multi-ply absorbent sheet when the plies are treated with debonder.

What is claimed is: 
     
       1. A method of making multi-ply absorbent sheet comprising:
 (a) providing a first absorbent cellulosic basesheet; 
 (b) providing a second absorbent cellulosic basesheet, 
 (c) interposing a ply-bonding agent or adhesive composition between said first absorbent cellulosic basesheet and said second absorbent cellulosic basesheet, and 
 (d) plying said first absorbent cellulosic basesheet with said second absorbent cellulosic basesheet by pressing them together with the NFC containing ply-bonding agent or adhesive composition interposed therebetween, 
 
       wherein the ply-bonding agent or adhesive composition is characterized by a viscosity and a surface tension, said agent or composition comprising:
 (e) water; 
 (f) nanofibrillated cellulose; and 
 (g) one or more modifiers effective to modify either or both of (i) the viscosity of the ply-bonding agent or the adhesive composition or (ii) the surface tension of the ply-bonding agent or the adhesive composition, 
 
       wherein the one or more modifiers are selected from the group consisting of components (iii), (iv), (v), (vi), (vii) or (viii), wherein: (iii) is PVOH and a viscosity modifier; (iv) is a viscosity modifier; (v) is a viscosity modifier and a surface tension modifier other than PVOH; (vi) is a water-soluble cellulose derivative; (vii) is a water soluble polyol; and (viii) is a surface tension modifier other than PVOH and wherein the ply-bonding agent or the adhesive composition contains 90 wt. % or more water. 
     
     
       2. The method of making multi-ply absorbent sheet according to  claim 1 , wherein at least one of said first absorbent cellulosic basesheet or said second absorbent cellulosic basesheet is treated with a debonder composition. 
     
     
       3. The method of making multi-ply absorbent sheet according to  claim 2 , wherein at least one of the first absorbent cellulosic basesheet or the second cellulosic basesheet are treated with debonder composition in an amount of from 1 lb of debonder composition per ton of cellulosic papermaking fiber used to make the basesheet to 16 lbs of debonder composition per ton of papermaking fiber used to make the basesheet. 
     
     
       4. The method of making a multi-ply absorbent sheet according to  claim 3 , wherein at least one of the first absorbent cellulosic basesheet or the second cellulosic basesheet are treated with debonder composition in an amount of from 2 lbs of debonder composition per ton of cellulosic papermaking fiber used to make the basesheet to 10 lbs of debonder composition per ton of papermaking fiber used to make the basesheet. 
     
     
       5. The method of making a multi-ply absorbent sheet according to  claim 1 , wherein the ply-bonding agent or the adhesive composition includes a viscosity modifier. 
     
     
       6. The method of making a multi-ply absorbent sheet according to  claim 5 , wherein the viscosity modifier comprises xanthan gum. 
     
     
       7. The method of making a multi-ply absorbent sheet according to  claim 6 , wherein the weight ratio of nanofibrillated cellulose:viscosity modifier in the ply-bonding agent or adhesive composition is from 1:0.13 to 1:0.2. 
     
     
       8. The method of making a multi-ply absorbent sheet according to  claim 5 , wherein the weight ratio of nanofibrillated cellulose:viscosity modifier in the ply-bonding agent or adhesive composition is from 1:0.05 to 1:0.5. 
     
     
       9. The method of making a multi-ply absorbent sheet according to  claim 1 , wherein PVOH is present in an amount of from 0.5 percent by weight to 3 percent by weight based on the weight of the agent or the aqueous composition. 
     
     
       10. The method of making a multi-ply absorbent sheet according to  claim 1 , wherein the agent or the composition contains from 0.35 percent by weight to 1.5 percent by weight of nanofibrillated cellulose based on the weight of the agent or the composition. 
     
     
       11. A method of making multi-ply absorbent sheet comprising:
 (a) providing a first absorbent cellulosic basesheet; 
 (b) providing a second absorbent cellulosic basesheet, 
 
       wherein at least one of the first absorbent cellulosic basesheet or the second cellulosic basesheet are treated with debonder composition in an amount of from 1 lb of debonder composition per ton of cellulosic papermaking fiber used to make the basesheet to 16 lbs of debonder composition per ton of papermaking fiber used to make the basesheet;
 (c) interposing an NFC containing ply-bonding adhesive between said first absorbent cellulosic basesheet and said second absorbent cellulosic basesheet,
 wherein the NFC containing ply-bonding adhesive comprises water, nanofibrillated cellulose and one or more additional components selected from the group consisting of components (i), (ii), (iii) and (iv), wherein: (i) is PVOH; (ii) is PVOH and a viscosity modifier; (iii) is a viscosity modifier and (iv) is a viscosity modifier and a surface tension modifier other than PVOH and wherein the ply-bonding adhesive contains 90 wt. % or more water; and 
 
 (d) plying said first absorbent cellulosic basesheet with said second absorbent cellulosic basesheet by pressing them together with the NFC containing ply-bonding adhesive interposed therebetween. 
 
     
     
       12. The method of making a multi-ply absorbent sheet according to  claim 11 , wherein the process comprises:
 (e) feeding said first absorbent cellulosic basesheet to an embossing nip; 
 (f) embossing a pattern of raised embossments in said first absorbent cellulosic basesheet; 
 (g) applying the NFC containing ply-bonding adhesive to the raised embossments of said first absorbent cellulosic basesheet; and 
 (h) plying said second absorbent cellulosic basesheet with said first absorbent cellulosic basesheet by pressing said second absorbent cellulosic basesheet to the adhesive disposed on the raised embossments of said first absorbent cellulosic basesheet. 
 
     
     
       13. The method of making a multi-ply absorbent sheet according to  claim 11 , wherein the multi-ply basesheet comprises a third absorbent cellulosic basesheet plied together with the first and second ply. 
     
     
       14. The method of making a multi-ply absorbent sheet according to  claim 11 , wherein the NFC containing ply-bonding adhesive comprises:
 (i) water; 
 (ii) polyvinyl alcohol; and 
 (iii) nanofibrillated cellulose, and wherein the NFC ply-bonding adhesive comprises from 90-98.5% by weight of the adhesive water, from 0.5% to 10% by weight of the adhesive polyvinyl alcohol and from 0.05% to 2.5% by weight of the adhesive nanofibrillated cellulose. 
 
     
     
       15. The method of making a multi-ply absorbent sheet according to  claim 14 , wherein the weight ratio of nanofibrillated cellulose:PVOH is 0.1 or greater and up to 0.5. 
     
     
       16. A multi-ply absorbent sheet comprising:
 (a) a first absorbent ply of absorbent cellulosic basesheet; 
 (b) a second absorbent ply of absorbent cellulosic basesheet, 
 (c) a ply-bonding agent or adhesive composition interposed between said first absorbent ply and said second absorbent ply, said ply-bonding agent or adhesive composition adhering said absorbent plies together, 
 
       wherein the ply-bonding agent or adhesive composition as applied between said first absorbent ply and said second absorbent ply comprises:
 (d) water 
 (e) nanofibrillated cellulose; and 
 (f) one or more modifiers selected from the group consisting of components (iii), (iv), (v), (vi), (vii) or (viii), wherein: (iii) is PVOH and a viscosity modifier; (iv) is a viscosity modifier; (v) is a viscosity modifier and a surface tension modifier other than PVOH; (vi) is a water-soluble cellulose derivative; (vii) is a water soluble polyol; and (viii) is a surface tension modifier other than PVOH and wherein the ply-bonding agent or adhesive composition contains 90 wt. % or more water. 
 
     
     
       17. The multi-ply absorbent sheet according to  claim 16 , wherein at least one of said first absorbent ply of absorbent cellulosic basesheet or said second absorbent ply of cellulosic basesheet is treated with a debonder composition. 
     
     
       18. The multi-ply absorbent sheet according to  claim 16 , wherein at least one of the first absorbent cellulosic basesheet or the second cellulosic basesheet are treated with debonder composition in an amount of from 1 lb of debonder composition per ton of cellulosic papermaking fiber used to make the basesheet to 16 lbs of debonder composition per ton of papermaking fiber used to make the basesheet. 
     
     
       19. The multi-ply absorbent sheet method of making a multi-ply absorbent sheet according to  claim 18 , wherein at least one of the first absorbent cellulosic basesheet or the second cellulosic basesheet are treated with debonder composition in an amount of from 2 lbs of debonder composition per ton of cellulosic papermaking fiber used to make the basesheet to 10 lbs of debonder composition per ton of papermaking fiber used to make the basesheet. 
     
     
       20. A method of making multi-ply absorbent sheet comprising:
 (a) providing a first absorbent cellulosic basesheet; 
 (b) providing a second absorbent cellulosic basesheet, 
 (c) interposing a ply-bonding agent or adhesive composition between said first absorbent cellulosic basesheet and said second absorbent cellulosic basesheet, and said agent or composition consisting essentially of: (e) water; (f) nanofibrillated cellulose; and (g) xanthan gum 
 (d) plying said first absorbent cellulosic basesheet with said second absorbent cellulosic basesheet by pressing them together with the NFC containing ply-bonding agent or adhesive composition interposed therebetween.